Before filling packaging containers with liquid foodstuff it is common to perform a sterilization procedure, in which a liquid or vaporized sterilization agent is injected into the interior of the packaging container in order to eliminate any microorganisms present.
Within the field of the present applicant the packaging container is formed from a laminated material comprising layers of paper and thermoplastic material. The choice of thermoplastic material as well as the presence of any further layers, such as aluminium foil or other metal foil, or additional barrier layers, will depend on the type of product to be contained and the desired shelf-life for such product. A minimum criterion is that the interior of the packaging container should not absorb moisture to the extent that the integrity of the packaging container is jeopardized. In most cases the same is true for the outside. Further barrier layers, of which aluminium foil is one example, may be arranged to prevent light or oxygen from diffusing into the packaging container after it has been sealed. Such measures may be desired in instances where an extended shelf-life is desired. While these measures relate to what can be done in order to maintain the conditions after a packaging container is filled and sealed, the present invention is closer related to the measures performed in order to obtain proper conditions prior to filling of the container.
An example is disclosed in the publication EP-1 046 585 by the present applicant, which should be sufficient in order for the skilled person to grasp the background and aid in realization of the beneficial features of the present invention.